Organic light emitting diode display device and organic light emitting diode thereof

ABSTRACT

There is provided an organic light emitting diode display device. The organic light emitting diode display device includes a substrate divided into an emission area and a non-emission area, an overcoating layer disposed on the substrate and including a plurality of micro lenses, a plurality of first electrode patterns disposed on the overcoating layer and spaced away from each other in the emission area, an organic emission layer disposed on the plurality of first electrodes, and a second electrode disposed on the organic emission layer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from Korean Patent Application No.10-2015-0134674, filed on Sep. 23, 2015, which is hereby incorporated byreference for all purposes as if fully set forth herein.

BACKGROUND Field of the Disclosure

The present disclosure relates to an organic light emitting diode, andmore particularly, to a display device including an organic lightemitting diode with improved light extraction efficiency.

Description of the Related Art

An organic light emitting diode display device is a self-light emittingdisplay device and, unlike a liquid crystal display device, does notneed a separate light source. Thus, the organic light emitting diodedisplay device can be lightweight and have a compact size. Further, theorganic light emitting diode display device is driven at a low voltage,which reduces power consumption, which is an advantageous feature of theorganic light emitting diode display device. Also, the organic lightemitting diode display device has excellent color expression ability, ahigh response speed, a wide viewing angle, and a high contrast ratio(CR). Therefore, the organic light emitting diode display device hasbeen researched as a next-generation display device.

Light emitted from an organic emission layer of the organic lightemitting diode generally passes through various elements in the organiclight emitting diode display device to the outside. However, a part ofthe light emitted from the organic emission layer may not be transmittedto the outside of the organic light emitting diode display device butmay be confined within the organic light emitting diode display device,which reduces the light extraction efficiency of the organic lightemitting diode display device.

For example, in a bottom-emission organic light emitting diode displaydevice, about 50% of the light emitted form an organic emission layer isconfined within the organic light emitting diode display device due tototal reflection or light absorption at an anode electrode, and about30% of the light emitted from the organic emission layer is confinedwithin the organic light emitting diode display device due to totalreflection or light absorption at a substrate.

As such, about 80% of the light emitted from the organic emission layeris confined within the organic light emitting diode display device andonly about 20% of the light is transmitted to the outside. Thus, theorganic light emitting diode display device has low luminous efficiency.

In order to improve the light extraction efficiency of the organic lightemitting diode display device, a method of forming a micro lens array(MLA) on an overcoating layer of the organic light emitting diodedisplay device has been developed. However, even if the micro lens arrayis formed on the overcoating layer of the organic light emitting diodedisplay device, a large amount of light is confined within the device,and only a small amount of light is transmitted to the outside.

Further, because the micro lens array is formed on the overcoatinglayer, emission areas of the organic light emitting diode display devicemay differ in luminous efficiency. Thus, a bright image may be formed inan area with a high luminous efficiency, and a dark image maybe formedin an area with a low luminous efficiency.

Accordingly, there has been a demand for an organic light emitting diodedisplay device that can improve luminous efficiency.

SUMMARY

An aspect of the present disclosure provides an organic light emittingdiode display device that can minimize a difference in brightnessbetween emission areas of the organic light emitting diode displaydevice and improve light extraction efficiency.

According to an aspect of the present disclosure, there is provided anorganic light emitting diode display device including a substratedivided into an emission area and a non-emission area, an overcoatinglayer disposed on the substrate and including a plurality of microlenses, a plurality of first electrode patterns disposed on theovercoating layer and spaced away from each other in the emission area,an organic emission layer disposed on the plurality of the firstelectrodes, and a second electrode disposed on the organic emissionlayer.

Herein, in an area where the micro lens is disposed, the organic lightemitting diode display device may be divided into a first area, a secondarea, and a third area depending on the thickness of the organicemission layer. In this case, the first area corresponds to a recessedarea of the micro lens, the second area corresponds to a slope of themicro lens, and the third area corresponds to a protruding area of themicro lens.

Further, the plurality of first electrode patterns may be disposed onlyin the second area and the third area of the organic light emittingdiode display device. In this case, the second area and the third areamay be emission areas of the organic light emitting diode display deviceand the first area may be a non-emission area.

In another aspect of the present disclosure, the plurality of firstelectrode patterns may be disposed only in the third area of the organiclight emitting diode display device. In this case, the third area may bean emission area of the organic light emitting diode display device andthe first area and the second area may be non-emission areas of theorganic light emitting diode display device.

According to another aspect of the present disclosure, an organic lightemitting diode display device includes a substrate, an overcoatinglayer, a first electrode pattern, an organic emission layer and a secondelectrode. The overcoating layer is disposed on the substrate andincludes a plurality of micro lenses, and each of the micro lensesincludes a recess. The first electrode pattern is disposed on theovercoating layer and has at least one opening corresponding to therecess. The organic emission layer is disposed on the substrate. Thesecond electrode is disposed on the organic emission layer, and theorganic emission layer is disposed between the first electrode patternand the second electrode.

In one aspect of the present disclosure, the organic light emittingdiode display device has a first area, a second area, and a third area,and each of the micro lenses further includes a protrusion and a slope.The first area corresponds to the recess, the second area corresponds tothe slope, and the third area corresponds to the protrusion.

In one aspect of the present disclosure, the organic emission layer in adirection perpendicular to the slope in the second area has a smallerthickness than the organic emission layer disposed in the first area andthe third area.

In one aspect of the present disclosure, the organic emission layer ofthe organic light emitting diode is disposed in contact with theovercoating layer in an area corresponding to the recess.

In one aspect of the present disclosure, each of the plurality of microlenses further includes a protrusion and a slope, and the firstelectrode pattern is disposed in an area corresponding to theprotrusion.

In one aspect of the present disclosure, the area corresponding to theprotrusion is an emission area, and an area corresponding to the slopeand the recess is a non-emission area.

In one aspect of the present disclosure, the organic emission layer ofthe organic light emitting diode is disposed in contact with theovercoating layer in an area corresponding to the recess and the slope.

In one aspect of the present disclosure, the overcoating layer isexposed at at least one opening.

In one aspect of the present disclosure, the first electrode patternincludes at least two convex portions spaced away from each other by atleast one opening.

In one aspect of the present disclosure, an organic light emitting diodeincludes a first electrode pattern, an organic emission layer and asecond electrode. The first electrode pattern has at least one opening.The organic emission layer is disposed on the first electrode pattern.The second electrode is disposed on the organic emission layer, and theorganic emission layer is disposed between the first electrode patternand the second electrode.

In the organic light emitting diode display device according to thepresent disclosure, the plurality of first electrode patterns is spacedaway from each other in an organic light emitting diode disposed on theovercoating layer including the plurality of micro lens. Thus, theorganic light emitting diode display device can minimize a difference inbrightness between emission areas and improve light extractionefficiency.

In another aspect of the present disclosure, the plurality of micro lensmay be formed in various shapes, and the plurality of first electrodepatterns may be spaced away from each other. Thus, the organic lightemitting diode display device can minimize a difference in brightnessbetween the emission areas and improve light extraction efficiency.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features and other advantages of thepresent disclosure will be more clearly understood from the followingdetailed description taken in conjunction with the accompanyingdrawings, in which:

FIG. 1 is a schematic diagram illustrating a display device according toan exemplary embodiment of the present disclosure;

FIG. 2 is a cross-sectional view of an organic light emitting diodedisplay device to which exemplary embodiments of the present disclosurecan be applied;

FIG. 3A is a plan view of an organic light emitting diode display deviceto which a micro lens is applied;

FIG. 3B is a cross-sectional view taken along a line A-B of the organiclight emitting diode display device of FIG. 3A;

FIG. 4 is a plan view illustrating an area where a micro lens isdisposed in an organic light emitting diode display device according toan exemplary embodiment of the present disclosure;

FIG. 5 is a cross-sectional view taken along a line C-D of the organiclight emitting diode display device of FIG. 4;

FIG. 6 is a diagram illustrating a micro lens and an organic lightemitting diode according to another exemplary embodiment;

FIG. 7 is a plan view illustrating an area where a micro lens isdisposed in an organic light emitting diode display device according toyet another exemplary embodiment of the present disclosure;

FIG. 8 is a cross-sectional view taken along a line E-F of the organiclight emitting diode display device of FIG. 7;

FIG. 9 is a graph illustrating light extraction efficiency as a functionof wavelength of an organic light emitting diode display deviceaccording to an exemplary embodiment of the present disclosure and anorganic light emitting diode display device according to ComparativeExample; and

FIG. 10 is a table comparing light extraction efficiency of the organiclight emitting diode display device according to an exemplary embodimentof the present disclosure and the organic light emitting diode displaydevice according to Comparative Example.

DETAILED DESCRIPTION OF THE EMBODIMENT

Hereinafter, exemplary embodiments of the present disclosure will bedescribed in detail with reference to the accompanying drawings. Theexemplary embodiments introduced hereinafter are provided as examples inorder to convey their spirits to a person having ordinary skill in theart. Therefore, the present disclosure is not limited to the followingexemplary embodiments and can be embodied in different shapes anddifferent arrangements. Also, the size and thickness of the device mightbe exaggerated for the sake of convenience in the drawings. Likereference numerals generally denote like elements throughout the presentspecification.

Advantages and features of the present disclosure, and methods foraccomplishing the same will be more clearly understood from exemplaryembodiments described below with reference to the accompanying drawings.The exemplary embodiments are provided only to complete disclosure ofthe present disclosure and to fully provide a person having ordinaryskill in the art to which the present disclosure pertains with thecategory of the disclosure, and the present disclosure will be definedby the appended claims.

When an element or layer is referred to as being “on” another element orlayer, it may be directly on the other element or layer, or interveningelements or layers may be present. Meanwhile, when an element isreferred to as being “directly on” another element, any interveningelements may not be present.

The spatially-relative terms such as “below”, “beneath”, “lower”,“above”, and “upper” may be used herein for ease of description todescribe the relationship of one element or components with anotherelement(s) or component(s) as illustrated in the drawings. It will beunderstood that the spatially relative terms are intended to encompassdifferent orientations of the element in use or operation, in additionto the orientation depicted in the drawings. For example, if the elementin the drawings is turned over, elements described as “below” or“beneath” other elements would then be oriented “above” the otherelements. Thus, the exemplary term “below” can encompass both anorientation of above and below.

Further, in describing components of the present disclosure, terms suchas first, second, A, B, (a), and (b) can be used. These terms are usedonly to differentiate the components from other components. Therefore,the nature, order, sequence, and the like of the correspondingcomponents are not limited by these terms.

FIG. 1 is a schematic diagram illustrating a display device according toan exemplary embodiment of the present disclosure. Referring to FIG. 1,a display device 1000 according to exemplary embodiments includes adisplay panel 1100 on which a plurality of first lines VL1 to VLm areformed in a first direction, i.e. a vertical direction, and a pluralityof second lines HL1 to HLn are formed in a second direction, i.e. ahorizontal direction, a first driver 1200 configured to supply a firstsignal to the plurality of first lines VL1 to VLm, a second driver 1300configured to supply a second signal to the plurality of second linesHL1 to HLn, and a timing controller 1400 configured to control the firstdriver 1200 and the second driver 1300.

On the display panel 1100, a plurality of pixels P are defined byintersection between the plurality of first lines VL1 to VLm formed inthe first direction and the plurality of second lines HL1 to HLn formedin the second direction.

Each of the first driver 1200 and the second driver 1300 may include atleast one driver integrated circuit (IC) configured to output a signalfor displaying an image.

The plurality of first lines VL1 to VLm formed in the first direction onthe display panel 1100 may be, for example, data lines configured totransfer a data voltage (first signal) to a vertical column of pixels,and the first driver 1200 may be, for example, a data driver configuredto supply the data voltage to the data lines.

Further, the plurality of second lines HL1 to HLn formed in the seconddirection on the display panel 1100 may be, for example, gate linesformed in the horizontal direction and configured to transfer a scansignal (first signal) to a horizontal column of pixels, and the seconddriver 1300 may be, for example, a gate driver configured to supply thescan signal to the gate lines.

The display panel 1100 may further include a pad in order to beconnected to the first driver 1200 and the second driver 1300. If thefirst driver 1200 supplies the first signal to the plurality of firstlines VL1 to VLm, the pad transfers the first signal to the displaypanel 1100, and if the second driver 1300 supplies the second signal tothe plurality of second lines HL1 to HLn, the pad transfers the secondsignal to the display panel 1100.

Each pixel includes one or more subpixels. The subpixel refers to a unitin which a specific kind of color filter is formed, or in which a colorfilter is not formed but an organic light emitting diode emits a lightof a specific color. Herein, colors to be defined in the subpixels mayinclude red (R), green (G), blue (B), and optionally white (W), but thepresent disclosure is not limited thereto. Each subpixel includes aseparated thin-film transistor and an electrode connected thereto, and,thus, hereinafter, a subpixel will also be referred to as a pixel area.A first line may be disposed in each subpixel, and a plurality ofsubpixels constituting a pixel may share a specific first line. Theconfiguration of a pixel/subpixel and a first line/second line can bemodified in various ways, and the present disclosure is not limitedthereto.

An electrode connected to a thin-film transistor and configured tocontrol emission of each pixel area on the display panel 1100 will bereferred to as a first electrode, and an electrode disposed on theentire surface of the display panel or disposed to include two or morepixel areas will be referred to as a second electrode.

If the first electrode is an anode electrode, the second electrode is acathode electrode, and vice versa. In the following, the first electrodewill be described as an anode electrode and the second electrode will bedescribed as a cathode electrode in an exemplary embodiment, but thepresent disclosure is not limited thereto.

Further, in the organic light emitting diode display device according toexemplary embodiments of the present disclosure, three or four subpixelsmay constitute one pixel. Furthermore, a color filter of a single colormay be disposed on one pixel, or a color filter may not be disposed onat least one of subpixels constituting the one pixel. The color filtercan convert a color of a single organic emission layer into a colorhaving a specific wavelength.

Moreover, each subpixel includes a light-scattering layer in order toimprove light extraction efficiency of the organic emission layer. Thelight-scattering layer may be referred to as a micro lens array, a nanopattern, a diffusion pattern, silica beads, or the like.

In the following, the light-scattering layer will be described as amicro lens array, but exemplary embodiments of the present disclosureare not limited thereto.

In the exemplary embodiments of the present disclosure, variousstructures capable of scattering lights may be combined and applied.

FIG. 2 is a cross-sectional view of an organic light emitting diodedisplay device to which exemplary embodiments of the present disclosurecan be applied, including a thin-film transistor Tr and an organic lightemitting diode EL electrically connected to the thin-film transistor Tr.

The thin-film transistor Tr includes an active layer 120, a gateelectrode 140, a source electrode 170, and a drain electrode 180.Further, the organic light emitting diode EL includes a first electrode210, an organic emission layer 230, and a second electrode 240.

Specifically, the active layer 120 of the thin-film transistor Tr isdisposed on a substrate 100. A gate insulation film 130 and a gateelectrode 140 are disposed on the active layer 120. An interlayerinsulation film 150 is disposed on the gate electrode 140.

Further, the source electrode 170 and the drain electrode 180 aredisposed to be in contact with the active layer 120 through a contacthole formed in the interlayer insulation film 150 are disposed on theinterlayer insulation film 150. A protective layer 160 is disposed onthe source electrode 170 and the drain electrode 180. The organic lightemitting diode display device to which exemplary embodiments of thepresent disclosure can be applied is not limited to FIG. 2. The organiclight emitting diode display device to which exemplary embodiments ofthe present disclosure can be applied may further include a buffer layer(not shown) disposed between the substrate 100 and the active layer 120.

Further, an overcoating layer 200 is disposed on the protective layer160. The first electrode 210 of the organic light emitting diode ELconnected to the drain electrode 180 of the thin-film transistor Tr isdisposed on the overcoating layer 200. Further, a bank pattern 220 isdisposed on the overcoating layer 200 so as to expose a part of a topsurface of the first electrode 210. The organic emission layer 230 isdisposed on the bank pattern 220 and the top surface of the firstelectrode 210 exposed by the bank pattern 220.

Herein, the organic emission layer 230 may be disposed only on the topsurface of the first electrode 210 exposed by the bank pattern 220, ormay be disposed on the first electrode 210 and the bank pattern 220.Further, the second electrode 240 of the organic light emitting diode ELis disposed to be overlapped with the organic emission layer 230 and thebank pattern 220.

Further, although not illustrated in the drawing, a polarizing plate maybe disposed on a rear surface of the substrate 100. The polarizing platemay be a polarizing plate having a polarization axis in a certaindirection and configured to transmit only a light having an axis in thesame direction as the polarization axis when the amount of lights isemitted from the rear surface of the substrate 100.

The polarizing plate may be formed as a single layer or a multilayer.Further, the polarizing plate has been described as having apolarization axis in a certain direction, but exemplary embodiments ofthe present disclosure are not limited thereto. The polarizing plate mayfurther include a phase retardation film.

Further, although not illustrated in FIG. 2, a color filter layerdisposed on the protective layer 160 may be further included in theorganic light emitting diode display device to which exemplaryembodiments of the present disclosure can be applied. Herein, the colorfilter layer may be disposed only on some of the plurality of subpixels.

Further, although FIG. 2 illustrates a bottom-emission type organiclight emitting diode display device, exemplary embodiments of thepresent disclosure may be applied to a top-emission or dual-emissionorganic light emitting diode display device, if necessary.

In order to improve light extraction efficiency of the above-describedorganic light emitting diode display device, an overcoating layer may beprovided on which a micro lens including a plurality of recesses and aplurality of protrusions may be formed.

In this case, when light is incident on an interface between the microlens and the first electrode 210 of the organic light emitting diode,light having an incidence angle equal to or lower than a totalreflection critical angle is extracted to the outside of the substrate100 without modification. Further, light having an incident angle higherthan the total reflection critical angle may collide with the microlens, thereby changing the path of the light before being extracted tothe outside of the substrate 100.

Accordingly, the light extraction efficiency of the organic lightemitting diode display device to which the micro lens is applied can beimproved. However, there may be a difference in light extractionefficiency between emission areas.

Details thereof will be described below with reference to FIG. 3A andFIG. 3B. FIG. 3A is a plan view of an organic light emitting diodedisplay device to which a micro lens is applied. FIG. 3B is across-sectional view taken along a line A-B of the organic lightemitting diode display device of FIG. 3A. Herein, description of thecomponents identical to those of FIG. 2 may be omitted and redundantdescription may also be omitted.

Referring to FIG. 3A and FIG. 3B, the organic light emitting diodedisplay device is divided into a first area 10, a second area 20, and athird area 30 depending on the thickness of the organic emission layer230 of the organic light emitting diode EL. Herein, the first area 10,the second area 20, and the third area 30 may be included in an emissionarea EA of the organic light emitting diode display device.

The organic emission layer 230 of the organic light emitting diode ELdisposed in the second area 20 may have a smaller thickness than theorganic emission layer 230 disposed in the first area 10 and the thirdarea 30. Specifically, since the organic emission layer 230 is formed bya deposition method having straightness, the organic emission layer 230in the second area 20 corresponding to a slope may have a smallerthickness than the organic emission layer 230 in the first area 10 andthe third area 30 in a direction perpendicular to the slope in thesecond area 20.

In other words, the second area 20 may be an area corresponding to aslope of a plurality of micro lenses formed on the overcoating layer200. Further, each of the first area 10 and the third area 30 may be anarea except the area corresponding to the slope of the plurality ofmicro lenses. Herein, the first area 10 corresponds to a recessed area(recess) of a micro lens, and the third area 30 corresponds to aprotruded area (protrusion) of the micro lens.

In the organic light emitting diode display device to which the microlens is applied, the first area 10, the second area 20, and the thirdarea 30 may be alternately disposed in the emission area EA.

Meanwhile, since the organic emission layer 230 has a small thickness inthe second area 20, the organic light emitting diode EL mainly emitslight in the second area 20. Further, most of the light transmitted fromthe slope is incident on the other areas of the micro lenses, and ismultiply reflected to decrease the incidence angle at the interface ofthe substrate, such that the incident angle is lower than the totalreflection critical angle, thereby preventing total internal reflection.Thus, the light extraction efficiency can be increased. Furthermore, theorganic emission layer 230 has the smallest thickness in the second area20 and thus has a high current density. Therefore, the organic lightemitting diode EL may have a high luminous efficiency in the second area20.

Moreover, the organic emission layer 230 in the third area 30corresponding to a protruded area of the micro lens has a greaterthickness than the organic emission layer 230 on the slope of the microlens and thus has a low current density. However, light extractionefficiency is high in the third area 30 due to the micro lens becausethe emission layer in the third area 30 also has a smaller thicknessthan the thickness thereof in the first area 10.

Accordingly, an image in the second area 20 and the third area 30 may beobserved as being brighter than an image in the first area 10.

Hereinafter, the following exemplary embodiments of the presentdisclosure are provided to solve the above-described problem, where theorganic light emitting diode display device has a plurality of firstelectrode patterns disposed spaced away from each other on anovercoating layer including a plurality of micro lenses. Thus,brightness is uniform across an emission area and light extractionefficiency can be further increased.

FIG. 4 is a plane view illustrating a part of an area where a micro lensis disposed in an organic light emitting diode display device accordingto an exemplary embodiment of the present disclosure. Referring to FIG.4, each area where a micro lens is disposed may have a hexagonal shapein a plan view, and the plurality of areas where a plurality of microlenses may be disposed may be formed into a hexagonal honeycombstructure in a plan view.

However, the area where a micro lens is disposed in the organic lightemitting diode display device according to an exemplary embodiment ofthe present disclosure is not limited thereto, and may have variousshapes such as an overall hemispheric shape, semi-elliptical shape orsquare shape.

Further, the area where a micro lens is disposed may be divided into afirst area 510, a second area 520, and a third area 530 depending on thethickness of the organic emission layer of an organic light emittingdiode. Herein, a first electrode of the organic light emitting diode maybe disposed only in the first area 510 and the second area 520. That is,the first electrode may not be disposed in the third area 530.Therefore, the first area 510 and the second area 520 may be emissionareas and the third area 530 may be a non-emission area.

This configuration will be described below in detail with reference toFIG. 5. FIG. 5 is a cross-sectional view taken along a line C-D of theorganic light emitting diode display device of FIG. 4. Referring to FIG.5, in the organic light emitting diode display device according to anexemplary embodiment of the present disclosure, a plurality ofinsulation layers 150 and 160 are disposed on the substrate 100 and theovercoating layer 200 including a plurality of micro lenses is disposedon the insulation layer 160. A maximum width of the micro lens isdesignated D1 and the full width at half maximum of the micro lens isdesignated F1, as illustrated in FIG. 5. Herein, the maximum width andthe full width at half maximum of the micro lens may be defined as awidth of the protrusion of the micro lens at the position correspondingto half the height of the micro lens. The overcoating layer, forexample, is made of photoresist material. The full width at half maximumof the micro lens may be determined by an exposure amount of lightirradiated to the overcoating layer and a material of the overcoatinglayer during a process of forming the micro lens.

The organic light emitting diode EL including a plurality of firstelectrode patterns 310, the organic emission layer 230, and the secondelectrode 240 is disposed on the plurality of micro lenses. Herein, thefirst electrode patterns 310, the organic emission layer 230, and thesecond electrode 240 may be formed according to the morphology of themicro lenses.

Herein, the first electrode pattern 310 may be disposed only in thesecond area 520 corresponding to a slope of a micro lens and the thirdarea 530 corresponding to a protruded area of the micro lens. That is,the first electrode pattern 310 may not be disposed in the first area510 corresponding to a recessed area of the micro lens.

Specifically, the organic emission layer 230 of the organic lightemitting diode EL disposed on the micro lens in the first area 510 has agreater thickness and thus has a low current density. Further, most ofthe light incident on the recessed area of the micro lens has anincident angle higher than the total reflection critical angle in thefirst area 510. Thus, a small amount of light is multi-reflected by themicro lens. Therefore, light extraction efficiency is decreased in thefirst area 510.

The organic light emitting diode display device according to anexemplary embodiment of the present disclosure includes an area wherethe first electrode pattern 310 is not disposed in the first area 510.Thus, a current does not flow in the first area 510. That is, theorganic emission layer 230 and the overcoating layer 200 may be disposedin contact with each other in the first area 510. Therefore, a greateramount of current flows in the second area 520 and the third area 530.

According to an exemplary embodiment of the present disclosure, thefirst electrode pattern 310 has at least one opening corresponding tothe recess (recessed area) of the micro lens. As shown in FIG. 5, aplurality of openings may be present, and a part of the overcoatinglayer 200 may be exposed at the plurality of openings to be in contactwith the organic emission layer 230.

In another exemplary embodiment of the present disclosure, the firstelectrode pattern 310 may include at least two convex portions spacedaway from each other by the at least one opening. As shown in FIG. 5, aplurality of both the at least two convex portions and the at least oneopening may be present. The convex portions may be located on the secondarea 520 corresponding to the slope of the micro lens and the third area530 corresponding to the protrusion of the micro lens. In one of themicro lenses, the convex portions are spaced away from each other by theopening located on the first area 510.

Accordingly, a current density increases in the second area 520 and thethird area 530, and thus, the light extraction efficiency in the secondarea 520 and the third area 530 increases.

An area where the first electrode pattern 310 is not disposed may be anon-emission area NEA of the organic light emitting diode displaydevice, and an area where the first electrode pattern 310 is disposedmay be an emission area EA of the organic light emitting diode displaydevice. Therefore, since the first electrode pattern 310 is not disposedin the first area 510 having a lower brightness than the second area 520and the third area 530, a difference in brightness between the emissionareas EA can be minimized. That is, in the organic light emitting diodedisplay device according to an exemplary embodiment of the presentdisclosure, the first electrode pattern 310 is not disposed in the firstarea 510 having low current density and light extraction efficiency,and, thus, there is an effect of increasing light extraction efficiencyin the second area 520 and the third area 530.

Further, the micro lens of the organic light emitting diode displaydevice according to the present disclosure is not limited to the microlens illustrated in FIG. 5, but may be formed in a shape illustrated inFIG. 6. FIG. 6 is a diagram illustrating a micro lens and an organiclight emitting diode according to another exemplary embodiment.

Referring to FIG. 6, a maximum width D2 of a micro lens formed on anovercoating layer 201 is smaller than a maximum width D1 of the microlens illustrated in FIG. 5. Therefore, a full width at half maximum(FWHM) F2, which is a width of a protrusion of the micro lens at aposition corresponding to half the height of the micro lens, may also besmaller than a full width at half maximum F1 of the micro lensillustrated in FIG. 5.

Since the maximum width D2 and the full width at half maximum F2 of themicro lens are decreased, the slope of the micro lens is steep. Thus, athickness of the organic emission layer 230 formed on the slope may befurther decreased. Therefore, the organic emission layer 230 may have asmaller thickness in the second area 520 corresponding to the slope ofthe micro lens.

Accordingly, the first area 510 may have a lower light extractionefficiency than the second area 520 and the third area 530. Meanwhile,as illustrated in FIG. 6, even if the maximum width D2 and the fullwidth at half maximum F2 of the micro lens are decreased, the pluralityof first electrode patterns 310 of the organic light emitting diode ELmay be disposed as being spaced away from each other. Accordingly, agreater amount of current flows in the second area 520 and the thirdarea 530, and the light extraction efficiency can be further improved inthe second area 520 and the third area 530.

Hereinafter, an organic light emitting diode display device according toyet another exemplary embodiment of the present disclosure will bedescribed with reference to FIG. 7 and FIG. 8. FIG. 7 is a plan viewillustrating a part of an area where a micro lens is disposed in theorganic light emitting diode display device. FIG. 8 is a cross-sectionalview taken along a line E-F of the organic light emitting diode displaydevice of FIG. 7.

First, referring to FIG. 7, the area where the micro lens is disposedmay be divided into the first area 510, the second area 520, and thethird area 530 depending on a thickness of an organic emission layer ofan organic light emitting diode. Herein, a first electrode of theorganic light emitting diode may be disposed only in the third area 530.

That is, the first electrode is not disposed in the first area 510 andthe second area 520. Therefore, the third area 530 may be an emissionarea and the first area 510 and the second area 520 may be non-emissionareas.This configuration will be described below in detail with reference toFIG. 8. In FIG. 8, a first electrode pattern 410 may be disposed only inthe third area 530 corresponding to the protruded area of the micro lensformed on the overcoating layer 200.

That is, the first electrode pattern 410 may not be disposed in thefirst area 510 corresponding to the recessed area of the micro lens andthe second area 520 corresponding to the slope of the micro lens.Herein, since the first electrode pattern 410 is not disposed in thefirst area 510 and the second area 520, the organic emission layer 230of the organic light emitting diode EL may be disposed in contact withthe overcoating layer 200 in the first area 510 and the second area 520.

Specifically, the organic emission layer 230 disposed in the third area530 has a greater thickness than the organic emission layer 230 disposedin the second area 520 and thus has a relatively low current density.However, the third area 530 has a higher light extraction efficiencythan the first area 510 and the second area 520. Thus, since the firstelectrode pattern 410 is formed only in the third area 530, the currentdensity of the third area 530 can be increased and the light extractionefficiency can be maximized.

In other words, since the first electrode pattern 410 is not disposed inthe first area 510 and the second area 520, current may flow andconcentrate in the organic light emitting diode EL disposed in the thirdarea 530, thereby increasing the current density of the organic lightemitting diode EL disposed in the third area 530 and increasing thelight extraction efficiency.

Meanwhile, an area where the first electrode pattern 410 is not disposedmay be a non-emission area NEA of the organic light emitting diodedisplay device, and an area where the first electrode pattern 410 isdisposed may be an emission area EA of the organic light emitting diodedisplay device. Therefore, since the first electrode pattern 410 is notdisposed in the first area 510 and the second area 520, only the thirdarea 530 having the highest light extraction efficiency may be theemission area EA. Thus, a difference in brightness between emissionareas EA can be suppressed.

That is, in the organic light emitting diode display device according toyet another exemplary embodiment of the present disclosure, the firstelectrode pattern 410 is not disposed in the first area 510, which haslower current density and light extraction efficiency than the thirdarea 530, and the second area 520, which has a lower light extractionefficiency than the third area 530. Thus, the light extractionefficiency in the third area 530 increases.

This effect will be described below with reference to FIG. 9 and FIG.10. FIG. 9 is a graph illustrating light extraction efficiency dependingon wavelength in an organic light emitting diode display deviceaccording to an exemplary embodiment of the present disclosure and anorganic light emitting diode display device according to ComparativeExample.

In the organic light emitting diode display device according to anexemplary embodiment of the present disclosure, a plurality of microlenses is formed on an overcoating layer and a first electrode patternof an organic light emitting diode is not disposed in an areacorresponding to a recessed area of the micro lens. In comparison, in anorganic light emitting diode display device according to the ComparativeExample, the plurality of micro lenses are formed on an overcoatinglayer, and the first electrode of an organic light emitting diode isdisposed entirely on the micro lens.

Referring to FIG. 9, it can be seen that light in a visible lightwavelength range generally have a higher intensity in the organic lightemitting diode display device according to an exemplary embodiment ofthe present disclosure than in the organic light emitting diode displaydevice according to Comparative Example. That is, the amount of lightextracted in the visible light wavelength range is greater in theorganic light emitting diode display device according to an exemplaryembodiment of the present disclosure than in the organic light emittingdiode display device according to Comparative Example.

FIG. 10 is a table comparing light extraction efficiencies of theorganic light emitting diode display device according to an exemplaryembodiment of the present disclosure and the organic light emittingdiode display device according to Comparative Example.

Referring to FIG. 10, it can be seen that at almost the same drivingvoltage, the light extraction efficiency of the organic light emittingdiode display device according to an exemplary embodiment of the presentdisclosure is 14% higher than that of the organic light emitting diodedisplay device according to the Comparative Example.

As described above, in an organic light emitting diode display deviceaccording to exemplary embodiments of the present disclosure, a firstelectrode of an organic light emitting diode is not disposed in an areahaving low light extraction efficiency and current density or an areahaving a low light extraction efficiency. Thus, a current density can befurther increased in an area having high light extraction efficiency andcurrent density or an area having a high light extraction efficiency,and the overall light extraction efficiency can be maximized.

The features, structures, effects, and the like described in the aboveexemplary embodiments are included in at least one exemplary embodimentand but are not limited to one exemplary embodiment. In addition, thefeatures, structures, effects, and the like described in the respectiveexemplary embodiments may be executed by those skilled in the art whilebeing combined or modified with respect to other embodiments.Accordingly, it will be understood that contents related to thecombination and modification of the exemplary embodiments are alsoincluded within the scope of the present disclosure.

Further, it should be understood that the exemplary embodimentsdescribed above should be considered as being descriptive alone and notfor limiting the present disclosure. It will be understood by thoseskilled in the art that various other modifications and applications maybe made therein without departing from the spirit and scope of theexemplary embodiments. For example, respective components shown indetail in the exemplary embodiments may be executed while beingmodified.

1-20. (canceled)
 21. An organic light emitting diode, comprising: asubstrate including a pixel area; an overcoating layer disposed at thepixel area and including a plurality of micro lenses; a first electrodedisposed on the plurality of micro lenses; an organic emission layerdisposed on the first electrode; and a second electrode disposed on theorganic emission layer, wherein each of the plurality of micro lensesincludes a protrusion and a recess, and a thickness of the organicemission layer in an area corresponding to between the protrusion andthe recess is smaller than a thickness of the organic emission layer inan area corresponding to the recess.
 22. The organic light emittingdiode according to claim 21, wherein the thickness of the organicemission layer in the area corresponding to between the protrusion andthe recess is smaller than a thickness of the organic emission layer inan area corresponding to the protrusion.
 23. The organic light emittingdiode according to claim 21, wherein a thickness from a lower side ofthe organic emission layer to an upper side of the second electrode inthe between the protrusion and the recess is smaller than a thicknessfrom a lower side of the organic emission layer to an upper side of thesecond electrode in the area corresponding to the recess.
 24. Theorganic light emitting diode according to claim 21, wherein the firstelectrode has a pattern that is disposed in an area corresponding to theprotrusion.
 25. The organic light emitting diode according to claim 24,wherein each of the plurality of micro lenses further includes a slope,and the organic emission layer is disposed in contact with theovercoating layer in an area corresponding to the recess and the slope.26. The organic light emitting diode according to claim 21, wherein therecess of the plurality of micro lenses are arranged in a line along thefirst direction and staggered along the second direction.
 27. Theorganic light emitting diode according to claim 21, wherein the recessof each of the plurality of micro lenses has a hexagonal shape or ahoneycomb structure in plan view.
 28. The organic light emitting diodeaccording to claim 21, wherein the protrusion of each of the pluralityof micro lenses has a hexagonal shape or a honeycomb structure in planview.
 29. The organic light emitting diode according to claim 21,wherein the first electrode includes at least one hole overlapping withthe recess, wherein the overcoating layer is exposed at the at least onehole, and wherein the organic emission layer is disposed within the atleast one hole.
 30. The organic light emitting diode according to claim21, wherein the first electrode includes: at least one hole overlappingwith the recess, and at least two convex portions spaced away from eachother by the at least one hole.
 31. An organic light emitting diodedisplay device comprising: a substrate; an overcoating layer on thesubstrate and including a plurality of micro lenses; an organic emissionlayer on the plurality of micro lenses; a first electrode between theovercoating layer and the organic emission layer; and a second electrodeon the organic emission layer, wherein each of the plurality of microlenses includes a protrusion and a slope, and wherein a thickness of theorganic emission layer in an area corresponding to the slope is smallerthan a thickness of the organic emission layer in an area correspondingto the protrusion.
 32. The organic light emitting diode display deviceto claim 31, wherein each of the plurality of micro lenses furtherincludes a recess, the slope being disposed between the protrusion andthe recess, and wherein an area corresponding to the protrusion and theslope is emission areas and an area corresponding to the recess isnon-emission area.
 33. The organic light emitting diode display deviceaccording to claim 31, wherein each of the plurality of micro lensesfurther includes a recess, the slope being disposed between theprotrusion and the recess, and the organic emission layer is disposed incontact with the overcoating layer in an area corresponding to therecess and the slope.
 34. The organic light emitting diode displaydevice according to claim 31, wherein the first electrode has a patternthat is disposed in an area corresponding to the protrusion.
 35. Theorganic light emitting diode display device to claim 34, wherein each ofthe plurality of micro lenses further includes a recess, the slope beingdisposed between the protrusion and the recess, and wherein an areacorresponding to the protrusion is emission areas and an areacorresponding to the slope and the recess is non-emission area.
 36. Theorganic light emitting diode display device according to claim 31,wherein each of the plurality of micro lenses further includes a recess,the slope being disposed between the protrusion and the recess, andwherein the recess of the plurality of micro lenses are arranged in aline along the first direction and staggered along the second direction.37. The organic light emitting diode display device according to claim31, wherein each of the plurality of micro lenses further includes arecess, the slope being disposed between the protrusion and the recess,and wherein the recess of each of the plurality of micro lenses has ahexagonal shape or a honeycomb structure in plan view.
 38. The organiclight emitting diode display device according to claim 31, wherein theprotrusion of each of the plurality of micro lenses has a hexagonalshape or a honeycomb structure in plan view.
 39. The organic lightemitting diode display device according to claim 31, wherein each of theplurality of micro lenses further includes a recess, the slope beingdisposed between the protrusion and the recess, wherein the firstelectrode includes at least one hole overlapping with the recess,wherein the overcoating layer is exposed at the at least one hole, andwherein the organic emission layer is disposed within the at least onehole.
 40. The organic light emitting diode display device according toclaim 31, wherein each of the plurality of micro lenses further includesa recess, the slope being disposed between the protrusion and therecess, and wherein the first electrode includes: at least one holeoverlapping with the recess, and at least two convex portions spacedaway from each other by the at least one hole.